1. Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering and Centre for Research in NanoEngineering; Universitat Politècnica de Catalunya (UPC); Diagonal 647 08028 Barcelona Spain
2. Institute for Advanced Study at the Department Chemie und Center of Integrated Protein Science München (CIPSM); Technische Universität München; Lichtenbergstrasse 4 85748 Garching Germany